The inventive concept relates to electronic design automation of a semiconductor device. More particularly, the inventive concept relates to a semiconductor device including standard cells and to electronic design automation thereof.
As the integration of semiconductor devices increases and the circuit configurations of semiconductor become more complicated, it is very difficult to design a layout of a semiconductor device manually. Thus, a semi-custom method of designing a layout of a semiconductor device using a computer is generally used. The semi-custom method is to provide a cell library in a design tool, produce a set of standard cells in advance using the cell library, and then layout using such standard cells. Such standard cells are generally each given a rectangular shape or footprint in the layout. Therefore, in the layout, i.e., as viewed in plan, each standard cell has two dimensions which will be referred to as a width and a height. The height is generally uniform among the standard cells and referred to as a unit height.
The standard cells represent components which can execute a logic function of the semiconductor device. That is, in a semi-custom method, various types of standard cells are generated and a semiconductor device is designed using such standard cells. To automatically design a semiconductor device, a site-row in which standard cells are disposed is generated and has a site row height corresponding to the unit height of standard cells. The unit height of the standard cells is determined basically by a size of an NMOS/PMOS included in (represented by one of the standard cells) and a minimum process design rule used when the set of standard cells for the device layout is generated. However, the unit height of the standard cells is designed to accommodate a whole number multiple of a basic spacing of metal lines (interval between adjacent ones of the metal lines) according to a standardized Floorplan rule supported by an electronic design automation (EDA) tool. Thus, the unit height of the standard cells has an additional overhead.